1. Field of the Invention
The present invention relates to a connector with a rear holder and a method of producing the connector, in which a housing and the rear holder are molded in a plurality of metal-molds, and thereafter the rear holder is provisionally retained on the housing by moving the metal-molds, and the rear holder can be completely retained after the insertion of connection terminals.
The present application is based on Japanese Patent Application No. Hei. 11-237262, which is incorporated herein by reference.
2. Description of the Related Art
There are known various examples of a rear holder-attached connector and a methods of producing the same, and such one example is disclosed in Unexamined Japanese Patent Publication No. Hei. 8-315896.
In a conventional rear holder-attached connector 51 shown in FIGS. 10 to 14, a rear holder 70, movable between a provisionally-retained position and a completely-retained position, is provided on a housing 52 in a straddling manner, and is held in the provisionally-retained position, the housing 52 having a plurality of terminal receiving chambers 53. Connection terminals 80 are inserted respectively into the terminal receiving chambers 53 from the rear side of the housing 52, and are retained respectively by housing lances 81 provided respectively within the terminal receiving chambers 53. Then, the rear holder 70 is held in the completely-retained position, thereby retaining the connection terminals 80 in a double manner.
More specifically, a forwardly downwardly-slanting, retaining hole or slot 72 is formed through each of opposite side walls 71 of the rear holder 70, and secondary retaining projections 73 for respectively retaining the connection terminals 80 in a secondary manner are formed on a lower surface of the rear holder 70 at a front end portion thereof. An upper side of each terminal receiving chamber 53 is open as at 53a at a central portion thereof, and the secondary retaining projection 73 is inserted obliquely downwardly into the terminal receiving chamber 53 through this opening 53a when the rear holder is moved from the provisionally-retained position to the completely-retained position. Forwardly downwardly-slanting, provisionally-retaining projections 54 are formed respectively on opposite side surfaces 52a of the housing 52, and also forwardly downwardly-slanting, completely-retaining projections 55 are formed respectively on the opposite side surfaces 52a, and are disposed obliquely forwardly of the provisionally-retaining projections 54, respectively. The projections 54, as well as the projections 55, are engageable in the retaining holes 72, respectively.
In the rear holder-attached connector of the above construction, when the rear holder 70 is pressed or pushed from a position above the rear end portion of the housing 52, the retaining holes 72 are retainingly fitted respectively on the provisionally-retaining projections 54, so that the rear holder 70 is held in the provisionally-retained position relative to the housing 52. Then, the connection terminals 80, each connected to a sheathed wire W, are inserted respectively into the terminal receiving chambers 53 from the rear side, and are primarily retained by the housing lances 81, respectively.
Then, when the rear holder 70 is pressed forwardly obliquely downwardly, the side walls 71 are elastically deformed laterally, so that each retaining hole 72 is disengaged from the provisionally-retaining projection 54, and advances obliquely forwardly, and a front end of each side wall 71 slides over the completely-retaining projection 55. Then, the retaining holes 72 are retainingly fitted on the completely-retaining projections 55, respectively, and at the same time the secondary retaining projections 73 are inserted respectively into the terminal receiving chambers 53 through the respective openings 53a to secondarily retain the connection terminals 80, respectively.
In the case where the housing 52 and the rear holder 70 are molded separately from each other, and then are brought to an assembling site where the housing and the rear holder are assembled together, the conveyance to the assembling side, the assembling step and an examination step are required, and besides a stock control for each of the housing 52 and the rear holder 70 is necessary.
To improve this, there has been proposed a rear holder-attached connector in which a rear holder 70 and a housing 52 are molded by a metal-mold assembly shown in FIG. 14, and also the rear holder 70 is attached to the housing 52 in a provisionally-retained condition, and then the two are removed from the metal-mold assembly.
The provisionally-retaining metal-mold assembly 90, shown in FIG. 14, comprises a fixed metal-mold 91, a first movable metal-mold 92 capable of moving upward and downward, and a pair of second movable metal-molds 93 and 93 capable of moving right and left. The housing 52 is molded by the fixed metal-mold 91, the first movable metal-mold 92 and inner sides of the second movable metal-molds 93 and 93. The rear holder 70 is molded by the fixed metal-mold 91, an outer side of the first movable metal-mold 92 and the inner sides of the second movable metal-molds 93 and 93.
First, the housing 52 and the rear holder 70 are molded by all of the metal-molds combined together, and then the first movable metal-mold 92 is moved downward, and then the second movable metal-molds 93 and 93 are moved right and left, respectively, that is, away from each other. As a result, the rear holder 70 and the housing 52 are molded, with the formed provisionally retained on the latter, and when the first movable metal-mold 92 is moved downward, the housing 52 and the rear holder 70 are discharged from the provisionally-retaining metal-mold assembly 90.
In the conventional rear holder-attached connector 51, however, the retaining holes 72 are retainingly engaged with provisionally-retaining projections 54 to hold the rear holder 70 on the housing 52 in the provisionally-retained condition, and also the retaining holes 72 are retainingly engaged with the completely-retaining projections 55 to hold the rear holder 70 on the housing 52 in the completely-retained condition. Therefore, in order that the rear holder will not move or shake relative to the housing in either of the two retained conditions, high dimensional accuracies are required, and this has invited problems that the productivity is lowered and that the cost increases.
And besides, with the provisionally-retaining metal-mold 90, the housing 52 and the rear holder 70 are molded in such a manner that the rear holder 70 is held on the housing 50 in the provisionally-retained condition. Therefore, it is necessary to provide a gap G1 between the inner surface of each side wall 71 of the rear holder 70 and the corresponding side surface of the housing 52, and also it is necessary to provide a gap G2 between the upper surface of the housing 52 and the lower surface of each secondary retaining projection 73 on the rear holder 70, as shown in FIG. 13.
Therefore, as shown in FIG. 14, a thin plate-like partition plate portion 94 for forming the gap G2 is formed on the fixed metal-mold 91, and thin plate-like partition wall portions 95 for respectively forming the gaps G1 are formed on the fixed metal-mold 91, and partition wall portions 96 are formed on the first movable metal-mold 92. And besides, a thin mold portion need to be provided between the outer periphery of each provisionally-retaining projection 54 and the inner peripheral edge of the corresponding retaining hole 72. The metal-molds have such thin plate portions, and this has invited a problem that the durability of the metal-molds is lowered.
With the above problems in view, it is an object of the present invention to provide a rear holder-attached connector in which high dimensional accuracy is not required for the molding operation, and a high yield is achieved, and the cost is low, and the durability of metal-molds is high.
To achieve the above object, according to the first aspect of the present invention, there is provided a connector which comprises a housing having a terminal receiving chamber into which a connection terminal is insertable, a rear holder attachable to the housing, the rear holder being operative to be held on the housing in one of a provisionally-retained condition and a completely-retained condition, wherein when the rear holder is provisionally retained on the housing, the connection terminal is insertable in the terminal receiving chamber, and when the rear holder is completely retained on the housing, the connection terminal is retained by the rear holder in the terminal receiving chamber, and a protective rib formed on the housing, the protective rib having portions outwardly projected from opposite side surfaces of the housing, wherein a distance between outer end surfaces of the portions of the protective rib is larger than a width of the rear holder.
In the connector of the aforementioned construction, since there is provided the protective rib which is larger in width than the rear holder, a molten resin can flow satisfactorily even when the terminal receiving chambers have thin walls, and therefore the yield is enhanced. As a result, the productivity is enhanced, and the cost is reduced.
According to the second aspect of the present invention, it is preferable that the rear holder includes opposite side walls having retaining holes which are respectively formed in inner surfaces thereof, and retaining pawls respectively formed on the inner surfaces and having forwardly downwardly-slanting surfaces, wherein the housing has provisionally-retaining projections respectively formed on the opposite side surfaces of the housing at a rear end portion thereof and respectively engaged in the retaining holes of the rear holder when the rear holder is provisionally retained on the housing, the provisionally-retaining projections each has a plurality of tapering surfaces, tapering retaining steps are formed on the housing and are disposed respectively adjacent to the provisionally-retaining projections, the tapering retaining steps are respectively engaged with the retaining pawls, and a forwardly downwardly-slanting abutment surface for guiding the rear holder is formed on an upper surface of the housing at the rear end portion thereof. Accordingly, the rear holder is held in the provisionally-retained position and the completely-retained position through the abutting engagement of the retaining pawls with the respective retaining steps and also through the abutting engagement of the inner surface (reverse surface) of the rear holder with the abutment surface. Namely, the movement of the rear holder for retaining purposes is effected through the relative wide surfaces, and therefore high dimensional accuracy is not required.
According to the third aspect of the present invention, it is preferable to provide a provisionally-retaining metal-mold assembly for molding the connector recited in the aforementioned first aspect of the present invention. Preferably, the provisionally-retaining metal-mold assembly comprises a pouring gate communicating with a plurality of gates which branch off from the pouring gate, a fixed metal-mold having at least one central gate among the plurality of gates being disposed in substantially parallel to the terminal receiving chamber, and a plurality of movable metal-molds movable relative to the fixed metal-mold, wherein the central gate of the fixed metal-mold communicates with a mold cavity portion formed by at least one of the movable metal-molds for molding the protective rib.
In the provisionally-retaining metal-mold assembly, the molten resin, poured through the central gate, flows through the mold cavity portion of the movable metal-mold for molding the relatively-wide protective rib, and then flows into relatively-narrow mold cavity portions for molding walls forming the terminal receiving chambers in the housing. Accordingly, the molten resin positively flows even into the narrow mold cavity portions, and the yield of the molded housings is enhanced, and the productivity is enhanced, and the cost is reduced.
Furthermore, to achieve the above object, according to the fourth aspect of the present invention, it is preferable to provide a method of producing a connector which includes a housing having a terminal receiving chamber into which a connection terminal is insertable, and a rear holder attachable to the housing, the rear holder being operative to be held on the housing in one of a provisionally-retained condition and a completely-retained condition, wherein when the rear holder is provisionally retained on the housing, the connection terminal is insertable in the terminal receiving chamber, and when the rear holder is completely retained on the housing, the connection terminal is retained by the rear holder in the terminal receiving chamber. Preferably, the method comprises forming a protective rib on the housing to have a distance between outer end surfaces thereof larger than a width of the rear holder, through a provisionally-retaining metal-mold assembly for molding the housing and the rear holder, wherein the provisionally-retaining metal-mold comprises a pouring gate and a plurality of gates branching off from the pouring gate, and includes a fixed metal-mold having at least one central gate among the plurality of gates being disposed in substantially parallel to the terminal receiving chamber, and a plurality of movable metal-molds movable relative to the fixed metal-mold, wherein the central gate of the fixed metal-mold communicates with a mold cavity portion formed by at least one of the movable metal-molds for molding the protective rib.